Pub Date : 2023-09-30DOI: 10.4283/jmag.2023.28.3.277
Chenguang Yang, Xiaolong Yang, Youming Zhou
At present, most of the seat suspensions of heavy-duty trucks use passive suspension and active suspension. The passive suspension has gradually failed to meet people"s needs in terms of vibration reduction performance, and the active suspension will consume too much energy. In this paper, a stepped by-pass valve magnetorheological semi-active suspension based on fuzzy PID control is proposed. The Simulink is used to simulate the system. In the case of sinusoidal excitation, the results show that this semi-active suspension reduces the vertical acceleration by 44.36%, the dynamic deflection of the suspension by 29.63% and the dynamic deformation of the tire by 43.78% compared with the passive suspension. Under the condition of C-level road surface input, the vertical acceleration of the suspension is reduced by 35.14%, the dynamic deflection of the suspension is reduced by 31.93%, and the dynamic deformation of the tire is reduced by 27.65%.
{"title":"Research on the Performance of Magnetorheological Semi-Active Suspension with Stepped By-Pass Valve based on Fuzzy PID Control","authors":"Chenguang Yang, Xiaolong Yang, Youming Zhou","doi":"10.4283/jmag.2023.28.3.277","DOIUrl":"https://doi.org/10.4283/jmag.2023.28.3.277","url":null,"abstract":"At present, most of the seat suspensions of heavy-duty trucks use passive suspension and active suspension. The passive suspension has gradually failed to meet people\"s needs in terms of vibration reduction performance, and the active suspension will consume too much energy. In this paper, a stepped by-pass valve magnetorheological semi-active suspension based on fuzzy PID control is proposed. The Simulink is used to simulate the system. In the case of sinusoidal excitation, the results show that this semi-active suspension reduces the vertical acceleration by 44.36%, the dynamic deflection of the suspension by 29.63% and the dynamic deformation of the tire by 43.78% compared with the passive suspension. Under the condition of C-level road surface input, the vertical acceleration of the suspension is reduced by 35.14%, the dynamic deflection of the suspension is reduced by 31.93%, and the dynamic deformation of the tire is reduced by 27.65%.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135040818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-30DOI: 10.4283/jmag.2023.28.3.317
Geonwoo Baek, Jinhyun Jeong, Min Park, Byungkeun Na, Seul Chan Hong, Jong-Gu Kwak
Dipole magnet for a neutral beam injector is a magnetic device deflecting residual ions to an ion dump. For the high power neutral beam injection to fusion plasma, the heat load on the surface of the residual ion dump should be under acceptable level. We investigate the magnetic lens effect of the bending magnet for beam expansion cases. To intensify the magnetic lens effect, the height of the field clamp in the magnetic core is adjusted. The COMSOL Multiphysics software is employed to calculate a magnetic flux density for the dipole magnet, to trace an ion beam trajectory, and to evaluate a heat distribution on the beam dump. Simulation results reveal that the longitudinal magnetic field at the magnet entrance has a significant effect on the heat distribution in the ion dump surface, and hence the local heat flux is considerably alleviated by the field clamp with adjusting the height of the clamp.
{"title":"Reinforcement of the Magnetic Lens Effect in the Dipole Magnet for a Neutral Beam Injector","authors":"Geonwoo Baek, Jinhyun Jeong, Min Park, Byungkeun Na, Seul Chan Hong, Jong-Gu Kwak","doi":"10.4283/jmag.2023.28.3.317","DOIUrl":"https://doi.org/10.4283/jmag.2023.28.3.317","url":null,"abstract":"Dipole magnet for a neutral beam injector is a magnetic device deflecting residual ions to an ion dump. For the high power neutral beam injection to fusion plasma, the heat load on the surface of the residual ion dump should be under acceptable level. We investigate the magnetic lens effect of the bending magnet for beam expansion cases. To intensify the magnetic lens effect, the height of the field clamp in the magnetic core is adjusted. The COMSOL Multiphysics software is employed to calculate a magnetic flux density for the dipole magnet, to trace an ion beam trajectory, and to evaluate a heat distribution on the beam dump. Simulation results reveal that the longitudinal magnetic field at the magnet entrance has a significant effect on the heat distribution in the ion dump surface, and hence the local heat flux is considerably alleviated by the field clamp with adjusting the height of the clamp.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135041136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-30DOI: 10.4283/jmag.2023.28.3.251
Novrita Idayanti, De di, Dadang Mulyadi, Tony Kristiantoro, Nanang Sudrajat, Gandi Sugandi, Azwar Manaf
This study aims to examine the effect of various composition ratios on the exchange spring effect of strontium ferrite (SrFeSUB12/SUBOSUB19/SUB)/cobalt ferrite (CoFe2O4) nanocomposite magnets. Nanoparticles of hexagonal hard phase SrFeSUB12/SUBOSUB19/SUB and spinel soft phase CoFeSUB2/SUBOSUB4/SUB were each prepared through mechanical alloying and high-power ultrasonic irradiation processes. Furthermore, the constituent of the hard-soft particles was weighed based on its ratios and the mixture was homogenized under a sonicator-type Qsonica at a frequency of 20 kHz for an hour. The bulk composite samples were obtained in cylindrical pellets form through compaction of mixture powders at 5000 kg/cm2, followed by sintering at 1200 °C. The exchange spring effect enhanced the magnetic properties, surpassing the normal limit for non-interacting magnetic particles due to enhanced grain interactions. The results showed that the degree of property enhancement depended on the various composition ratios and microstructure of the composite magnets. The magnetization of saturation (MSUBs/SUB) of the samples increased compared to a single SrFeSUB12/SUBOSUB19/SUB. Furthermore, the highest coercivity (HSUBc/SUB) and product energy maximum (BH)SUBmax/SUB values were observed in the sample which had mass ratios of SHF:COF of 85:15 with coded S80C20. The occurrence of exchange spring effects was observed in material characterized by a microstructure consisting of a hard-magnetic phase with elevated magnetocrystalline anisotropy and saturation magnetization values, along with a soft magnetic phase exhibiting high saturation magnetization value.
{"title":"Effect of Various Composition Ratios on the Exchange Spring Effect in SrFe<SUB>12</SUB>O<SUB>19</SUB>/CoFe<SUB>2</SUB>O<SUB>4</SUB> Nanocomposite Magnets","authors":"Novrita Idayanti, De di, Dadang Mulyadi, Tony Kristiantoro, Nanang Sudrajat, Gandi Sugandi, Azwar Manaf","doi":"10.4283/jmag.2023.28.3.251","DOIUrl":"https://doi.org/10.4283/jmag.2023.28.3.251","url":null,"abstract":"This study aims to examine the effect of various composition ratios on the exchange spring effect of strontium ferrite (SrFeSUB12/SUBOSUB19/SUB)/cobalt ferrite (CoFe2O4) nanocomposite magnets. Nanoparticles of hexagonal hard phase SrFeSUB12/SUBOSUB19/SUB and spinel soft phase CoFeSUB2/SUBOSUB4/SUB were each prepared through mechanical alloying and high-power ultrasonic irradiation processes. Furthermore, the constituent of the hard-soft particles was weighed based on its ratios and the mixture was homogenized under a sonicator-type Qsonica at a frequency of 20 kHz for an hour. The bulk composite samples were obtained in cylindrical pellets form through compaction of mixture powders at 5000 kg/cm2, followed by sintering at 1200 °C. The exchange spring effect enhanced the magnetic properties, surpassing the normal limit for non-interacting magnetic particles due to enhanced grain interactions. The results showed that the degree of property enhancement depended on the various composition ratios and microstructure of the composite magnets. The magnetization of saturation (MSUBs/SUB) of the samples increased compared to a single SrFeSUB12/SUBOSUB19/SUB. Furthermore, the highest coercivity (HSUBc/SUB) and product energy maximum (BH)SUBmax/SUB values were observed in the sample which had mass ratios of SHF:COF of 85:15 with coded S80C20. The occurrence of exchange spring effects was observed in material characterized by a microstructure consisting of a hard-magnetic phase with elevated magnetocrystalline anisotropy and saturation magnetization values, along with a soft magnetic phase exhibiting high saturation magnetization value.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135040967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-30DOI: 10.4283/jmag.2023.28.3.258
Haoen Xu, Jin Huang, Xinyu Xu, Junqiang Zheng
This paper presents how to select the proper slot and pole combination (SPC) and reasonable rotor topologies for an interior permanent-magnet (IPM) machine. Firstly, the selection principle of SPC is reported, and some electromagnet performances, including winding factor, stator space magneto-motive force (MMF) harmonics, radial force harmonics, and cogging torque, are analyzed and compared. Secondly, four PM rotor topologies are designed and discussed, including surface permanent-magnet (SPM), spoke type, V-shape, and multi-layer reluctance (MR) type. Their performances, such as back-EMFs, torque, and ripple and flux-weakening capability, are thoroughly analyzed and compared by the finite-element method (FEM). Finally, a 27-slot and 8-pole V-shape IPM machine is selected and designed optimally, which offers high power/torque density, high efficiency, and less torque ripple. In order to ensure the reliability of its rotor mechanical strength, the equivalent stress and deformation are analyzed by ANASY. Besides, its d-q axis mathematical model is built to verify its performance further. Then experiments on the prototypes are carried out for validation.
{"title":"Design and Analysis of the Interior Permanent-Magnet Machine Considering Slot-pole Combination and Rotor Topology","authors":"Haoen Xu, Jin Huang, Xinyu Xu, Junqiang Zheng","doi":"10.4283/jmag.2023.28.3.258","DOIUrl":"https://doi.org/10.4283/jmag.2023.28.3.258","url":null,"abstract":"This paper presents how to select the proper slot and pole combination (SPC) and reasonable rotor topologies for an interior permanent-magnet (IPM) machine. Firstly, the selection principle of SPC is reported, and some electromagnet performances, including winding factor, stator space magneto-motive force (MMF) harmonics, radial force harmonics, and cogging torque, are analyzed and compared. Secondly, four PM rotor topologies are designed and discussed, including surface permanent-magnet (SPM), spoke type, V-shape, and multi-layer reluctance (MR) type. Their performances, such as back-EMFs, torque, and ripple and flux-weakening capability, are thoroughly analyzed and compared by the finite-element method (FEM). Finally, a 27-slot and 8-pole V-shape IPM machine is selected and designed optimally, which offers high power/torque density, high efficiency, and less torque ripple. In order to ensure the reliability of its rotor mechanical strength, the equivalent stress and deformation are analyzed by ANASY. Besides, its d-q axis mathematical model is built to verify its performance further. Then experiments on the prototypes are carried out for validation.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135040965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-30DOI: 10.4283/jmag.2023.28.3.234
Lamouri Rachida, Ki Hyeon Kim
We report in this work the effects of the Polyvinylpyrrolidone (PVP) concentration on the solvothermal synthesis of FeSUB3/SUBOSUB4/SUB nanocluster with different PVP concentrations such as 5 mg/ml, 10 mg/ml, and 25 mg/ml. The effect of the PVP on the structural, microstructural, and magnetic properties was analyzed using different techniques. XRD patterns showed the crystallization of all samples in the cubic structure with an average crystallite size smaller than 10 nm. Homogeneous dispersion of the nanoparticles was shown for small concentrations of PVP, while the aggregation of the nanoparticles was observed for higher concentrations leading to the formation of uniform nanoclusters with an average size around 167 nm for a PVP concentration of 25 mg/ml. A soft ferromagnetic behavior was found for all prepared samples with a saturation magnetization of about 54.75 emu/g obtained for FeSUB3/SUBOSUB4/SUB nanoparticles with 10 mg/ml of PVP. Keywords : FeSUB3/SUBOSUB4/SUB nanocluster, solvothermal synthesis, PVP concentration
{"title":"Polyvinylpyrrolidone-assisted Solvothermal Synthesis of Fe<SUB>3</SUB>O<SUB>4</SUB> Nanoclusters","authors":"Lamouri Rachida, Ki Hyeon Kim","doi":"10.4283/jmag.2023.28.3.234","DOIUrl":"https://doi.org/10.4283/jmag.2023.28.3.234","url":null,"abstract":"We report in this work the effects of the Polyvinylpyrrolidone (PVP) concentration on the solvothermal synthesis of FeSUB3/SUBOSUB4/SUB nanocluster with different PVP concentrations such as 5 mg/ml, 10 mg/ml, and 25 mg/ml. The effect of the PVP on the structural, microstructural, and magnetic properties was analyzed using different techniques. XRD patterns showed the crystallization of all samples in the cubic structure with an average crystallite size smaller than 10 nm. Homogeneous dispersion of the nanoparticles was shown for small concentrations of PVP, while the aggregation of the nanoparticles was observed for higher concentrations leading to the formation of uniform nanoclusters with an average size around 167 nm for a PVP concentration of 25 mg/ml. A soft ferromagnetic behavior was found for all prepared samples with a saturation magnetization of about 54.75 emu/g obtained for FeSUB3/SUBOSUB4/SUB nanoparticles with 10 mg/ml of PVP. Keywords : FeSUB3/SUBOSUB4/SUB nanocluster, solvothermal synthesis, PVP concentration","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135040964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-30DOI: 10.4283/jmag.2023.28.3.286
Seungha Yoon
Considerable attention has been given to controlling magnetic anisotropy for future flexible spintronic devices because the magnetization behavior of magnetic thin film and device changes with the bending stress, which is known as the inverse-magnetostriction effect. The net magnetic anisotropy resulting from the fabrication process plays a significant role in determining the working functions for magnetic field applications. In this study, the variation of intrinsic magnetic anisotropy in permalloy thin films was investigated depending on the dcmagnetron sputtering position. The randomly formed magnetic easy-axis was finally controlled by the application of magnetic field during the sample deposition.
{"title":"Reducing Magnetic Anisotropy Variation of Permalloy Thin Films in the dc-Magnetron Sputtering","authors":"Seungha Yoon","doi":"10.4283/jmag.2023.28.3.286","DOIUrl":"https://doi.org/10.4283/jmag.2023.28.3.286","url":null,"abstract":"Considerable attention has been given to controlling magnetic anisotropy for future flexible spintronic devices because the magnetization behavior of magnetic thin film and device changes with the bending stress, which is known as the inverse-magnetostriction effect. The net magnetic anisotropy resulting from the fabrication process plays a significant role in determining the working functions for magnetic field applications. In this study, the variation of intrinsic magnetic anisotropy in permalloy thin films was investigated depending on the dcmagnetron sputtering position. The randomly formed magnetic easy-axis was finally controlled by the application of magnetic field during the sample deposition.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135041244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Iron-silicon thin films used as a single layer or in sandwich structures are currently regarded as a promising candidate in high magnetic sensors. A detailed understanding of magnetization dynamics in such thin films is of great interest. In this work, we only focused on modeling the magnetization reversal. Numerical solution to the nonlinear Landau-Lifshitz-Gilbert (LLG) equation can be used to conduct the study. With the help of our developed Matlab code, the simulations were carried out. External field strength, damping parameter and temperature all have an impact on the speed of the magnetization reversal. The validation of our computations is achieved via a separate simulation. It relates to the solution of the standard problem proposed by the micromagnetic Modeling Activity G roup (μMAG ). The results are in agreement with the ones presented in the National Institute of Standards and Technology (NIST) website.
{"title":"Magnetization Dynamics Modeling in a Like Iron-Silicon Thin Film by the Micromagnetic Approach","authors":"Messaoud Boufligha, Lakhdar Bessissa, Djillali Mahi","doi":"10.4283/jmag.2023.28.3.245","DOIUrl":"https://doi.org/10.4283/jmag.2023.28.3.245","url":null,"abstract":"Iron-silicon thin films used as a single layer or in sandwich structures are currently regarded as a promising candidate in high magnetic sensors. A detailed understanding of magnetization dynamics in such thin films is of great interest. In this work, we only focused on modeling the magnetization reversal. Numerical solution to the nonlinear Landau-Lifshitz-Gilbert (LLG) equation can be used to conduct the study. With the help of our developed Matlab code, the simulations were carried out. External field strength, damping parameter and temperature all have an impact on the speed of the magnetization reversal. The validation of our computations is achieved via a separate simulation. It relates to the solution of the standard problem proposed by the micromagnetic Modeling Activity G roup (μMAG ). The results are in agreement with the ones presented in the National Institute of Standards and Technology (NIST) website.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135041255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-30DOI: 10.4283/jmag.2023.28.3.323
Manh Kha Hoang, Thuc Kieu Xuan, Thanh Pham Xuan, Trung Kien Vu, Thanh Son Pham
This paper presents a design of magnetic resonant wireless power transfer (MR-WPT) system operating at 6.78 MHz with flexible resonator coils. The resonator coils are fabricated on an FR-4 substrate with a very thin thickness of 0.2 mm; therefore, they can be bent at various angles. With the bendable resonator coils, the configuration of the MR-WPT system will be more flexible, thereby increasing the applicability. However, the inductance, resistance, quality factor, and mutual inductance of the coils will be changed with the bending angle, thereby affecting the performance of the MR-WPT system. Detailed investigations of these changes were conducted by both simulation and experiment. Thus MR-WPT systems with flexible resonators can be designed for optimum performance. This proposed MR-WPT system can be applied in situations where system configuration requires high flexibility. Moreover, a bent resonator system can perform better than a flat resonator system in the inward bending configuration.
{"title":"A Design of Magnetic Resonant Wireless Power Transfer System using Flexible Resonator Coils","authors":"Manh Kha Hoang, Thuc Kieu Xuan, Thanh Pham Xuan, Trung Kien Vu, Thanh Son Pham","doi":"10.4283/jmag.2023.28.3.323","DOIUrl":"https://doi.org/10.4283/jmag.2023.28.3.323","url":null,"abstract":"This paper presents a design of magnetic resonant wireless power transfer (MR-WPT) system operating at 6.78 MHz with flexible resonator coils. The resonator coils are fabricated on an FR-4 substrate with a very thin thickness of 0.2 mm; therefore, they can be bent at various angles. With the bendable resonator coils, the configuration of the MR-WPT system will be more flexible, thereby increasing the applicability. However, the inductance, resistance, quality factor, and mutual inductance of the coils will be changed with the bending angle, thereby affecting the performance of the MR-WPT system. Detailed investigations of these changes were conducted by both simulation and experiment. Thus MR-WPT systems with flexible resonators can be designed for optimum performance. This proposed MR-WPT system can be applied in situations where system configuration requires high flexibility. Moreover, a bent resonator system can perform better than a flat resonator system in the inward bending configuration.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135041124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-30DOI: 10.4283/jmag.2023.28.3.290
Guo-Jun Yu, Shao-Jie Zhu, Cheng-Bin Du, Ling-Yun Wang, Jun-Chi Huang
This paper studies magnetic field control and velocity-activated magnetorheological shear thickening fluid (MR-STF). High-concentration STF is composed of nano-sized silica particles suspended in a solvent polyethylene glycol (PEG), and then micron-sized carbonyl iron particles of different mass fractions are added to the STF to manufacture different MR-STF. The rheometer is used to study the viscoelasticity of all four samples. The correlation between dynamic behavior and shear rate, angular frequency, and external magnetic field is studied and discussed. In the lower angular frequency range, the loss modulus is slightly larger than the storage modulus, and MR-STF behaves as a viscoelastic state. After the critical angular frequency, the storage modulus decreases sharply, well below the loss modulus. MR-STF appears in a viscous state and a liquid state. With the start of external field excitation, MR-STF is more inclined to MRF. Finally, the apparent viscosity and shear rate of MR-STF are fitted. The results show that with the increase of magnetic induction strength, the plastic viscosity coefficient of MR fluid increases, the flow characteristic index decreases, and the shear thinning effect becomes more significant.
{"title":"Study on the Magnetic Rate Sensitivity and Shear Properties of Magnetorheological Shear Thickening Fluid","authors":"Guo-Jun Yu, Shao-Jie Zhu, Cheng-Bin Du, Ling-Yun Wang, Jun-Chi Huang","doi":"10.4283/jmag.2023.28.3.290","DOIUrl":"https://doi.org/10.4283/jmag.2023.28.3.290","url":null,"abstract":"This paper studies magnetic field control and velocity-activated magnetorheological shear thickening fluid (MR-STF). High-concentration STF is composed of nano-sized silica particles suspended in a solvent polyethylene glycol (PEG), and then micron-sized carbonyl iron particles of different mass fractions are added to the STF to manufacture different MR-STF. The rheometer is used to study the viscoelasticity of all four samples. The correlation between dynamic behavior and shear rate, angular frequency, and external magnetic field is studied and discussed. In the lower angular frequency range, the loss modulus is slightly larger than the storage modulus, and MR-STF behaves as a viscoelastic state. After the critical angular frequency, the storage modulus decreases sharply, well below the loss modulus. MR-STF appears in a viscous state and a liquid state. With the start of external field excitation, MR-STF is more inclined to MRF. Finally, the apparent viscosity and shear rate of MR-STF are fitted. The results show that with the increase of magnetic induction strength, the plastic viscosity coefficient of MR fluid increases, the flow characteristic index decreases, and the shear thinning effect becomes more significant.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135040966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-30DOI: 10.4283/jmag.2023.28.3.304
Songhee Cheon, Jungyoon Kim, Misun Kang
This study investigated the effect of pulsed electromagnetic field (PEMF) on proprioception through static balance after the short-term application of PEMF in people with functional flat feet. Forty-two volunteers participated in the study. The proprioceptive index of all subjects was measured before and after exposure to PEMF for 1 week. Seventeen subjects with normal feet were not exposed to a PEMF (Group I), and PEMF was applied to 17 subjects with normal feet (Group II) and eight with functional flat feet (Group III). In Group I, there were no significant differences in any of the variables. In Group II, a significant difference was observed only in the medio-lateral value when perturbation was applied in the antero-posterior direction. In Group III, significant differences in medio-lateral, antero-posterior, and vertical values were observed when perturbation was applied in the medio-lateral direction in Group III. Although there was a learning effect with repeated measurements, the improvement in balance after PEMF application indicates that PEMF has a positive effect on the nervous system in subjects with functional flat feet.
{"title":"Short-Term Application of Pulsed Electromagnetic Fields for Static Balance of Functional Flatfeet","authors":"Songhee Cheon, Jungyoon Kim, Misun Kang","doi":"10.4283/jmag.2023.28.3.304","DOIUrl":"https://doi.org/10.4283/jmag.2023.28.3.304","url":null,"abstract":"This study investigated the effect of pulsed electromagnetic field (PEMF) on proprioception through static balance after the short-term application of PEMF in people with functional flat feet. Forty-two volunteers participated in the study. The proprioceptive index of all subjects was measured before and after exposure to PEMF for 1 week. Seventeen subjects with normal feet were not exposed to a PEMF (Group I), and PEMF was applied to 17 subjects with normal feet (Group II) and eight with functional flat feet (Group III). In Group I, there were no significant differences in any of the variables. In Group II, a significant difference was observed only in the medio-lateral value when perturbation was applied in the antero-posterior direction. In Group III, significant differences in medio-lateral, antero-posterior, and vertical values were observed when perturbation was applied in the medio-lateral direction in Group III. Although there was a learning effect with repeated measurements, the improvement in balance after PEMF application indicates that PEMF has a positive effect on the nervous system in subjects with functional flat feet.","PeriodicalId":16147,"journal":{"name":"Journal of Magnetics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135040971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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